<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <style>

        dot {
            display: inline-block;
            height: 1em;
            line-height: 1;
            text-align: left;
            vertical-align: -.25em;
            overflow: hidden;
        }
        dot::before {
            display: block;
            content: '...\A..\A.';
            white-space: pre-wrap;
            animation: dot 1s infinite step-start both;
        }
        @keyframes dot {
            33% { transform: translateY(-2em); }
            66% { transform: translateY(-1em); }
        }

    </style>
</head>
<body>
    正在加载中<dot>...</dot>
</body>
</html>